This invention relates to an article inspection device including separate detectors for primary and scattered radiation.
An example of the prior art is disclosed in U.S. Pat. No. 4,870,670, and is illustrated in FIG. 7.
As shown in FIG. 7, a fan-shaped X-ray beam 1 which is generated by X-radiator 2 and a collimator 3 is irradiated onto an article 4 which is conveyed by conveyor belt 5 in the direction of the arrow X. As a result of that, scattered X-ray beams are emitted by the article 4 in all directions.
A scintillator 6 receives a part of the emitted scattered X-ray beams through diaphragms 7 of a modulator 8 and generates visible rays. The visible rays generated from the scintillator 6 are converted into electrical signals by an opto-electrical transducer 9, so that the scattered X-ray beams are detected.
The detected scattered X-ray beams as an output from the opto-electrical transducer 9 are input into an image processor 10, and then the image of the region of the article 4 is generated.
The image is visually displayed on a TV monitor 11. The primary X-ray beams are detected by X-ray line sensor 12 and are displayed as a primary X-ray beam image by the TV monitor 11 through a multiplexer 13 and the image processor 10.
However, in this prior art, the efficiency of detecting the scattered radiation is remarkably low because the diaphragms of the modulator are small. Thus, noise occurs in the picture of the TV monitor.